Migrating VMs with Veeam Backup & Replication

I have been involved in a project, where we need to migrate hundreds of VMware VM's from one datacenter to another.

When thinking, that how we should do that migration, we decided to test if Veeam Replication functionality would be good for us. And it is. In our case, downtime for servers outside office hours, is mainly not an issue, so it did this even easier.

Why did we end up using Veeam?

• We are already using it as our backup solution, and also doing replication for DR purposes
• We have limited network capacity between datacenters, and Veeam compresses data while doing replication
• Network labels and subnets are different on datacenters, and Veeam can do IP address re-map, and also change VM's network, while doing replication, so it makes it faster to bring those servers back online at new DC.

How are we doing it?

We are having migration script, that does following steps

• Reads list of VMs that are in specific Veeam Replication job, used in migrations
• Shuts down those servers in old datacenter (tries to do it gently, but if it does not succeed, does brutal poweroff, none of which have happened so far)
• Changes some settings on those VM's before migration
• Starts Veeam Replication job to move servers to new datacenter

And when that is done, we manually do failover in Veeam, to start servers in new DC.

One notable thing about replication in our case. It would have been possible (and was our original idea), to migrate most of the data in beforehand, and when doing actual migration, just replicate changed data, and make actual migration time really short. Only problem is, that on old environment we noticed that CBT is corrupted on some machines, and it forced us to disable CBT on migration job.

Here is the script that we are using. It needs to run on Veeam Backup&Replication server, since we have not yet upgraded to v9.

This script can be run as a Scheduled task, so you can build your Replication job to be ready, and let this script do the work at night.

#Change these settings
$logpath = "c:\scripts\migration_log\"
$vCenter = "oldvcenter.vmware.local"
$vCenterUser "vmware\administrator"
$vCenterPass "P@ssw0rd"
$ReplicaJob = "VeeamReplicaJobName"

#Make sure that VMware snapins are loaded
if ( (Get-PSSnapin -Name VMware* -ErrorAction SilentlyContinue) -eq $null )
{
    Add-PsSnapin VMware*
}
#Add Veeam functions
& 'C:\Program Files\Veeam\Backup and Replication\Backup\Install-VeeamToolkit.ps1'


#This fuction is grabbed from: http://ict-freak.nl/2009/10/05/powercli-enabledisable-the-vm-hot-add-features/
Function Enable-vCpuHotAdd($vm){
    $vmview = Get-vm $vm | Get-View 
    $vmConfigSpec = New-Object VMware.Vim.VirtualMachineConfigSpec
    $extra = New-Object VMware.Vim.optionvalue
    $extra.Key="vcpu.hotadd"
    $extra.Value="true"
    $vmConfigSpec.extraconfig += $extra
    $vmview.ReconfigVM($vmConfigSpec)
}

#This fuction is grabbed from: http://ict-freak.nl/2009/10/05/powercli-enabledisable-the-vm-hot-add-features/
Function Enable-MemHotAdd($vm){
    $vmview = Get-vm $vm | Get-View 
    $vmConfigSpec = New-Object VMware.Vim.VirtualMachineConfigSpec
    $extra = New-Object VMware.Vim.optionvalue
    $extra.Key="mem.hotadd"
    $extra.Value="true"
    $vmConfigSpec.extraconfig += $extra
    $vmview.ReconfigVM($vmConfigSpec)
}

#https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1010048
Function Enable-AutoUpdate($vm){
 $vmview = $vm | Get-View
 $vmConfigSpec = New-Object VMware.Vim.VirtualMachineConfigSpec
 $vmConfigSpec.Tools = New-Object VMware.Vim.ToolsConfigInfo
 $vmConfigSpec.Tools.ToolsUpgradePolicy = "UpgradeAtPowerCycle"
 $vmview.ReconfigVM($vmConfigSpec)
}

#Starts logging of all activities in this script
$timestamp = get-date -Format yyyy.dd.MM.HH.mm.ss
$logfile = $logpath + $timestamp +".log"
start-transcript -path $logfile -append

#Connects to vCenter server
Connect-VIServer $vCenter -User $vCenterUser -Password $vCenterPass

#Gets list of VMs from replication job in Veeam 
$VMlist = Get-VBRJob -Name $ReplicaJob|Get-VBRJobObject|Where-Object {$_.type -like "Include"}|Select Name

write "VMs in replica job"
write $VMlist

# shutdown logic idea from: http://www.virtu-al.net/2010/01/06/powercli-shutdown-your-virtual-infrastructure/
$VMs = get-vm $VMlist.name
foreach($VM in $VMs)
{
 write "Shutting down VM " $VM.name
 $VM | Shutdown-VMGuest -Confirm:$false
}

#Set the amount of time to wait before assuming the remaining powered on guests are stuck 
$waittime = 1800 #Seconds

$Time = (Get-Date).TimeofDay
do {
    #Wait for the VMs to be Shutdown cleanly
    sleep 1.0
    $timeleft = $waittime - ($Newtime.seconds)
    $numvms = (Get-VM $VMlist.name | Where { $_.PowerState -eq "poweredOn" }).Count
    Write "Waiting for shutdown of $numvms VMs or until $timeleft seconds"
    $Newtime = (Get-Date).TimeofDay - $Time
    } 
 until ((@(Get-VM $VMlist.name | Where { $_.PowerState -eq "poweredOn" }).Count) -eq 0 -or ($Newtime).Seconds -ge $waittime)
 
 
$ForceShutdown = Get-VM $VMlist.name | Where { $_.PowerState -eq "poweredOn" }
 
if ($ForceShutdown) {
 Write "Starting forced poweroff for following servers"
 write $ForceShutdown
 Stop-VM $ForceShutdown -Confirm:$false
}

#Enable Memory hotadd, cpu hotadd and VMware tools autoupdate 
foreach($VM in $VMs)
{
 write "Change settings on VM: $VM"
 Enable-MemHotAdd $VM
 Enable-vCpuHotAdd $VM
 Enable-AutoUpdate $VM
}

#Finally start replication job
Start-VBRJob -Job $ReplicaJob